Safety door interlocking switch



R. L. DE CAMP. SAFETY DOOR INTERLOCKING SWITCH.

APPLICATIION FILED SEPT-25 1917- Patented Oct. 26, 1920.

UNITED STATES PATENT OFFICE.

ROY L. DE CAMP, OF LOS ANGELES, CALIFORNIA, ASSIGNOR T0 BAKER IRONWORKS, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

SAFETY DOOR INTERLOCKING SWITCH.

To all whom it may concern:

Be it known that I Ro L. DE CAMP, a citizen of the United tates residingat Los Angeles, in the county of Los Angeles and State of California,have invented a new and useful Safety Door Interlocking Switch, of whichthe following is a specification.

This invention pertains to switches of the character designed to beoperated by closing and opening movements of a closure or other memberand an object of the invention is to produce a device of this characterof minimum liability to become disarranged, and requiring minimumattention to keep in operative condition.

Another object is to construct a switch of which the operating memberthereof interlocks with a member mounted on the door.

Another object is to so construct the switch that the parts thereof willnot be subject to blows or shocks when the door is opened and closed.

Other objects and advantages will appear in the subjoined detaildescription.

The accompanying drawings illustrate the invention.

Figure 1. is a fragmental front elevation of a door structure with thenewly invented switch applied thereto, the door being shown in openposition in solid lines and in closed position in broken lines.

Fig. 2 is an enlarged side elevation of the switch shown in Fig. 1, theoperating member being in section. Solid lines indicate the operatingmember and switch arm in circuit'breaking position and broken linesindicate said member and arm interlocked n circuit-closing posltion.

Fig. 3 is a sectional elevation on line indicated by m w, Fig. 2.

Fig. 4 is a side elevation of the switch, the cover and switch arm beingomitted to expose to view the inside mechanism of the switch. 1

Fig. 5 is a reduced plan section on line indicated by 00 -40, Figs. 2and 4.

The invention is designed to be used in connection with any suitableclosure and is especially adapted to be used in connection with elevatordoors, and a door of this description is indicated at 1 in Fig. 1. Thedoor 1 is provided with an operating member of any suitableconstructionand in the drawings said member is shown in the form of apin 2 of circular cross section. The pin 7 Specification of LettersPatent.

Patented Oct. 26, 1920.

Application filed September 25, 1917. Serial No. 193,188.

2 is adapted to engage a T-shaped switch arm, said arm having laterallyextending members or limbs 3, 4 and a central rib 5 substantially atright angles to the members 3, 4. The rib 5 and limb 3 or limb 4together form an L-shaped arm. At the junction of the members 3, 4 withthe rib 5 are offset notches a, b respectively, said notches being ofsuitable shape to fit the operating memher 2 and in the instance shown,curved to fit said member. The switch arm also includes a flange 6connecting the members 3, 4 to a hub 7 of said switch-operating arm. Thehub 7 fits loosely on the outer projecting end of a stud 8 which istightly inserted in an internal boss 9 of a switch case 10, there beinga shoulder 11 on the stud 8 seated against the boss 9. The side of thecase 10 opposite the boss 9 is formed by a removable cover 12 fastenedin place by screws 13 or equivalents and provided with a central orifice14 to accommodate the inner end of the hub 7.

The hub 7 rests against the outer face of a drum 15 which is circularexcepting as hereinafter noted and which is constructed of any suitableelectric-insulating material, the drum 15 being keyed to the hub 7 so asto be rotated by turning of the switch-operating arm. In the instanceshown in the drawings the keying of the drum 15 to the hub 7 isaccomplished by pins 16 projecting from the hub 7 into sockets 17 formedin the drum 15 as clearly shown in Fig. 5. I Thus when theswitch-operating arm is turned the hub 7 and drum 15 are rotated on thestud 8. A washer 18 is preferably interposed between the stud shoulder11 and the drum 15 as shown in F ig; 3 and the washer 19 is placed onthe outer end of the stud 8 against the outer face of the hub 7. Thewasher 19 is held against outward displacement by any suitable means, inthe instance shown in v the drawings said means comprising a cotter pin20 inserted through a transverse hole 21 in the stud 8.

The drum 15 is provided on its curved periphery with semi-circularcontact mem bers 22, 23 mounted opposite to one another and fastened tothe drum by any suitable means such, for instance, as screws 24. The

drum 15 is cut away at one side to form a flat face 25 along whichextends a connector 26 which may be in the form of a copper strip orequivalent and which has its FAQ .. the cotter pins 46 the pins ets 33and each is ends inserted between the drum and the contacts 22, 23, twoof the screws 24 passlng through the ends of the connector 26 to firmlyhold it in place.

When the drum 15 is turned sufficiently, the contacts 22, 23 are adaptedto be engaged by other contact members 27, 28, each of which comprises astraight portion 29, an inwardly bent inwardly convex or semi-circularportion 30, and an end flange -3lengaged in'a transverse groove 32 of anequivalents 34, 35 to 35 maybe turned'up to hold the leads, not 7 shown,by whichthe switch is'electrically connected in the control circuit ofthe elevator or other circuit to be closed and opened by operation oftheswitch. Means are provided toyieldingly hold the contacts '27, 28 withtheir curved portions 30 in engagement with the contacts 22, 23 when thedrum is turned sufficiently far for that purpose and such means "areconstructed as follows, though it is understoodthat they may beotherwise constructed if desired. The straight portion 2901. eachcontact member 27,28 is provided with a perforation 41 to receive aheaded pin 42 which projects through a perforation 43 in the bracket 33,the head ofthe pin being at the'outer face of the "straight portion 29.Each pin 42 is provided with washers 44 and coil springs 45'between thewashers, "said washers and springs'being held in place by cotter pins46-passing throughholes 47 in the pins 42.

he expansive 'force of the springs 45 pulls theheads of the pins 12against the contacts 27, 28 so as to force the contact portions 30toward the drum 15 asis clearly understood.

It is-now clearthat-when'either of the contacts 22, 23 are in engagementwith the contact 27'electriccurrent will flow between the'binding posts35.

From the foregoing it is'clear that the switch is readily assembled anddisassembled for, by removing the cotter pin 20, the

washer 19, hub 7 and drum "15 may be slippedoff of the stud 8,

and by removing 42 may be withdrawn from the perforations 41, 43 soas'to :release the contacts27, 28.

vAssuming that the binding posts 35 are connectedin the circuitcontrolling the-operation of an elevator, it is clear that when theelevator door l .65;

is in the 'unclosed position shownuin solid lines .11 Fig. l the so thatthev electric circuit will be broken and that in order for the operatorto close the circuit so as to operate the elevator car it will benecessary for the door to be closed as in broken lines in Fig. 1 so asto swing the switch-operating arm a sufficiently far to cause engagementof the contact 27 with the contact 22.

As the pin 2 moves to the left in Fig. 2 it is clear that said pininterlocks with the switcl1operati11garm by reason of the offset, notcha, as clearly shown in broken lines 0, Fig. 2. it is also clear thatwhen the door 1 is opened the pin 2, because of its interlocking withthe switclroperating arm, will open the switch. Thus it is clear thatopening movement of the switch-operating arm as well as closing movementthereof is effected by movement of the elevator door and not through theagency of any spring,

weights or by gravity.

in devices of this character it is ofprime importance that the switchoperating means cooperate with the switch in such a manner as to preventoverthrow or backlash, for the reason that the closures to which saiddevice may be applied, are at times forcibly slammed shut with aconsequent perceptible rebound. The switch arm must therefore cooperatewith the operating pin in such a manner as to retain said arm againstoverthrow when forcibly engaged by the pin and also insucha manner thatthe arm will be immediately effected by any rebound movement of saidpin. p

In the present construction one of the offset notches closely engagesthe operating pin 2 during a switch operating movement therebyeffectively preventing overthrow of the "switch arm aheadof the pin whensaid pin engage the arm with'great force and also transmitting'anyrebound movement of the pin to the switch arm, so that the switch willnot be closed partly open position, due to a rebound thereof.

The switch parts are shown in the drawings as being assembledin'positions suitable for use with a door opening to the right, but theconstruction of the switch provides for assembling the'parts in positionso that the switch canrea'dily be used for adoor opening to the left andsuch assemblingis done as follows: The switch-operating arm 3, 4, 5, 6,7 will be operated in a reverse direction from that shown in Fig. 2 anditis clear that when the switch is placed in position in connection witha dooropeningto the left the pin 2 insaid door will engage the notch 6instead of the notch a.

It may be desirable under some conditions of installation toplacethes'witch case above or beneath the closure" and for this reasonthe drum 15 may be provided with holes 48 with the door stillinswitch-operating .arm' can be turned 90 degrees relative to the drumand the pins 16 will then seat in the holes 48.

In operation, rotation of the drum causes wiping or rubbing enga ementof the contacts 22, 23, 27, 28 thus cfeaning the contacts of any foreignmatter inimical to closing of l operation respectively of closing andopen-' ing the door and is not dependent upon springs, weights orgravity, thus making it impossible to open the door without opening theelevator controlling circuit and to close the door without closing thecircuit.

I claim:

1. The combination with a closure having a pin projectiig therefrom, ofa switch having an L-shaped operating arm provided with an offset notchat the junction of its limbs to fit the pin.

2. The combination with a closure having a pin projecting therefrom, ofa switch having a pivotally mounted L-shaped operating arm provided withan offset notch at the junction of its limbs to fit the pin.

A switch comprising a rotatively mounted drum, contacts mounted on saiddrum, other contacts, means to yieldingly hold said other contactstoward the drum, and an L-shaped arm connected with the drum to turn thedrum, said arm having an offset notch at the junction of its limbs forengagement with an operating member.

4:. The combination with a closure having a switch-operating memberprojecting therefrom, of a switch having a reversibly mounted armprovided with a pair of offset notches to fit the switch-operatingmember.

5. The combination with a closure having a pin projecting therefrom, ofa switch having a pivoted operating arm comprising angularly arrangedmembers, one of said arm members being parallel to the path of movementof the pin when the closure is in open position and the other arm memberextending at the same time vertically across the path of movement ofsaid pin, there being an offset notch at the junction of said armmembers adapted to receive a portion of the pin as the closure movesfrom open to closed position.

6. The combination with a closure having a pin projecting therefrom, ofa switch having a reversibly pivoted T-shaped operating arm, two of thelimbs of said arm being parallel to the path of movement of the pin whenthe closure is in open position and the other limb of the arm at thesame time extending vertically across the path of movement of the pin,there being an offset notch at the junction of the vertical limb witheach of the other limbs adapted to receive a portion of the pin as theclosure moves from open to closed position.

Signed at Los Angeles, California, this 7th day of September, 1917.

ROY L. DE CAMP.

lVitnesses:

W. S. HOAG, FRANK WESTALL.

